The Government stressed that the penalties levied at the initial decision stage “may be reduced, cancelled, increased or reissued at the objection or appeal stage”.

In a written parliamentary answer to Liberal Democrat leader Tim Farron, Mr Goodwill added: “Please also note that the collection figures are not cohort based statistics and therefore do not represent payment against penalties issued in a particular year.”

The figures show the number of civil penalties imposed to public and private limited companies, sole traders, partnerships and franchises for employing undocumented migrants.

In 2015/16, £46.2m of penalties were initially issued to firms for employing illegal immigrants, whereas only £12.5m was collected.

For the current financial year to September, a total of £24m in fines have been imposed, with £8.5m collected.

The lowest level of fines came in 2012/13, when £10.8m in initial penalties were imposed and £6.3m taken in payment.

Overall, there were 15,115 penalties issued from financial year 2009/10 to September 2016 for firms employing illegal immigrants.

PoliticsHome understands that fines can be reduced for firms who cooperate with Home Office investigations or for those who pay early.

Companies can also pay the penalties by instalments over 36 months. Previous fines are still being pursued by the Home Office.

It is understood that the spike in the number of penalties in 2015/16, when 2,594 fines were issued, stems from the Government’s renewed focus on combating illegal immigrants working in the UK.

Ministers have introduced measures such as working with insolvency companies to disbar directors who employ undocumented migrants in a bid to crackdown on the issue.

The 2016 Immigration Bill also grants powers to close down businesses for the practice.

AMNESTY

In November Boris Johnson reportedly renewed his call for illegal immigrants who have escaped detection for 10 years to be granted the right to stay in the UK following Brexit.

The Foreign Secretary suggested to ministers that allowing those who entered Britain illegally the right to stay could generate funds for the treasury as tax income would rise.

A Home Office spokesman said: “We are not looking afresh at an amnesty for illegal migrants, and will not be”.